#include<stdio.h>
#include<string.h>
int main()
{
	char s1[100],s2[100];
    int sum1=0,sum2=0;
	while(scanf("%s %s",&s1,&s2,s1!=0&&s2!=0))
	{
		if (strcmp(s1, "0") == 0 && strcmp(s2, "0") == 0) {
            break;
        }
		int i;
		for(i=0;i<strlen(s1);i++)
		{
		 	sum1=sum1*26+s1[i]-'a';
		}
		for(i=0;i<strlen(s2);i++)
		{
		 	sum2=sum2*26+s2[i]-'a';
		}
		if((sum1+sum2)%2==0)
		{
			printf("Yes\n");
		}
		else
		printf("No\n");
	}
	return 0;
}
